A compound represented by general formula (VII):
[wherein R2 represents a hydrogen atom or a halogen atom, Rc represents a C1-6 alkyl group, X represents a heteroaryl group or R13R14NCO—, R11 represents a hydrogen atom, a halogen atom, a cyano group, a C1-6 alkyl group, a C2-7 alkenyl group, a carbamoyl group or a C2-7 alkynyl group (where the C2-7 alkynyl group may optionally be substituted with a C1-4 acyl group), R13, R14, R16 and R17 each independently represent a hydrogen atom, a C1-6 alkoxy group, a C3-8 cycloalkyl group or a C1-6 alkyl group (where the C1-6 alkyl group may optionally be substituted with a cyano group, a halogen atom, a hydroxy group, a C1-6 alkoxy group or —NR23R24) the combination of R13 and R14 and the combination of R16 and R17 may each independently, together with the nitrogen atom to which they are bonded, optionally form a 4- to 6-membered heterocyclic group having at least one nitrogen atom, and R15, R23 and R24 each independently represent a hydrogen atom or a C1-6 alkyl group]or a pharmaceutically acceptable salt thereof (the compound or salt being also referred to hereunder as a “coumarin derivative of general formula (VII)”) is known to have pharmacological activity such as antitumor activity (see Patent document 1 or 2).
A method for producing a coumarin derivative of general formula (VII) is disclosed in Patent document 1 or 2. Patent document 1 or 2 discloses a method represented by the scheme below [In the scheme, DMF represents N,N-dimethylformamide, TBS represents a tert-butyldimethylsilyl group, dba represents dibenzylideneacetone, and BINAP represents 2,2′-bis(diphenylphosphino)-1,1′-binaphthyl. Also, the numerical values (%) and “quant.” given below some structural formulas indicate the yields of the respective compounds], for example (see the manufacturing example for “compound 1j-2-16-2K” in Patent document 1 or 2).
